Circuit interrupter



Feb. 3, 1948. PONSTINGL 2,435,322

CIRCUIT INTERRUPTER Filed March 29, 1945 2a 7 f if 25 17 24 64 WITNESSESI INVENTOR 1A? j/Zv M V Patented Feb. 3, 1948 CIRCUIT INTERRUPTER John 0. Ponstingl, Wiikinsburg, Pa., ..ssim' to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application March 29, 1945, Serial No. 585,461

10 Claims.

This invention relates to direct-current circuit interrupters and, more particularly, to arc-extinguishing structures therefor.

A general object of my invention is to provide an improved direct-current circuit interrupter which will more effectively extinguish the are drawn therein than has heretofore been achieved.

Another object is to provide an improved blowout structure for a direct-current circuit interrupter.

The problem of arc blowout is encountered,

.when applying direct-current relays or other cir cult interrupters for controlling such devices as magnetic motor-brakes, motor-field circuits, large ,contactor coils and various other devices, where the currents are elf-such magnitude to necessitate some type of arc blowout on the relays or interrupter contacts.

Present, practice is to use relays having magnetic blowouts, where the energy for the blowout flux is supplied either by a shunt or series coil. Sometimes, relay contacts are shunted by a con denser of a suitable size to aid in extinguishing the arc.

The limiting factors relating to a shunt blowout coil scheme are that it is dependent on the circuit voltage, which may produce heat, thereby renderin possible the burning out of the coil, and it must have a suitable source for excitation.

One of the limiting factors of a series current type blowout scheme is that the blowout coil can only be designed to be efiective over a certain current range. In other words, if the current to be interrupted is less than the minimum current for which the blowout coil was designed, the arc may not be extinguished when the switch contacts open to break the current circuit. This comes about because insufiicient ampere turns exist in the magnetic circuit, and, as a consequence, insuflicient magnetic blowout flux would be available for interruption of the arc.

The maximum operating current will be limited to the maximum heatin permissible in the blowout coil. Furthermore, there is a continuous generation of heat in the blowout coil circuit.

The disadvantage of using a, condenser shunting the arc is that the condenser may deteriorate with age and must be designed for a specific 'voltage and current. Since the condenser shunts the contacts, the problem of leakage is always present.

The purpose of my invention is to present a different form of magnetic blowout which has distinct advantages over the three present-day tactsl2 and I3.

schemes, as outlined above. This new method, in a sense, is blowout by induction.

Another object of my invention is to create magnetic flux in the blowout magnet of a directcurrent circuit interrupter by inductively coupling the blowout magnet with the operating magnet for the interrupter.

Another object is to provide an improved blowout magnet structure in a direct-current circuit interrupter and to provide improved means for inductively setting up magnetic flux in the blowout magnet for effecting extinction of the are drawn within the direct-current circuit interrupter.

Further objects and advantages will readily become apparent upon a reading of the following specification, taken in conjunction with the drawing, in which:

Figure 1 is a perspective somewhat diagram-= matic view of a direct-current circuit interrupter embodying my invention and shown in the opencircuit position;

Fig. 2 is a plan view of a relay embodying my invention and shown in the open-circuit position; and

Fig, 3 is a side elevational view of the relay shown in Fig. 2.

Referring to the drawing, and more particularly to Figure 1 thereof, the reference numeral I designates a panel upon which is mounted a directcurrent relay or interrupter generally designated by the reference numeral 2. The blowout magnet 3 for the interrupter comprises a U shaped magnet 4 secured by screws 5 to the panel I and inductively coupled to the operating magnet 8 of the interrupter by a copper strap 1. The movable armature 8 of the operating magnet 6 is pivotally mounted at 9 and is spring-biased to its open position by a tension spring ID.

A pigtail i I is electrically connected to the movable armature 8 and hence to the movable contact I2, the latter making contacting engagement with the stationary contact iii in the closedcircuit position. Preferably, a pigtail or lead It is connected to the stationary contact l3.

An operating coil I5 is wound about one leg l6 of the operating magnet 6 and serves, when energized, to set up magnetic flux in the operating magnet 6 to effect the closure of the movable armature 8 and hence to cause closure of the contacts I 2, l3. Upon deenergization of the magnet 6. the spring i0 causes separation of con- It will be apparent that, when the operating coil i5 is connected to a suitable source of direct-current excitation, the magnetic flux will build up in the operating magnet 8, and the fiux will die down upon opening of the circuit of coil ll. Both the buildin up and the dyins down or the magnetic flux in the magnet I induces a current in the copper strap 1, the latter linking all or the lines of flux passing through the operating magnet 8. The induced current in the copper strap 1 in turn causes a building up or magnetic flux in the U-shaped magnet I, to thereby set up a unidirectional magnetic field between the polepieces I1, I8 spaced laterally from the contact structure l2, l3.

From the foregoing, it will be apparent that, both during the opening and closing operations. there will be a change of flux in the operating magnet 6 and hence an induced current in the copper strap 1. Thus, during both the closing and opening operations, the induced current in the strap I will inductively cause a magnetic field to be created between the pole-pieces I I, II for blowing out the are between contacts I! and I3.

Figs. 2 and 3 show an application of the foregoing arrangement to a relay structure of conventional style, in which the operating magnet 6 comprises two legs I9, 20 and a bight p rtion 2|. The operating coil I5 is disposed about the leg 20 and the copper strap 1 links the other leg is. The operating magnet 8 is secured to the panel I by screws 22. The U-shaped magnet 4 is secured by screws 5 to the panel I. The stationary contact 13 is supported by an insulating bar 23 secured by screws 24 to the opposed legs 25, 26 of the blowout magnet 3.

Integrally formed with the insulating bar 23 are two opposed plate portions 21, 28 which serve to confine the are drawn between the stationary contact l3 and the movable contact l2. The movable contact I2 is mounted at the upper end of a movable armature 8, the latter being spring-biased to the open position by a tension spring ID. The armature 8 is pivoted about the pins 9, and a lead ll makes electrical contact with a support 28 to which the armature 8 is pivoted at 9. Another lead I4 is electrically connected to the stationary contact IS.

The operation of the relay structure set forth in Figs. 2 and 3 is identical to that previously described, namely that a magnetic flux is inductively created between the pole-pieces l1, it across the contact structure l2, l3, during both the opening and closing operations, by virtue of the presence of the strap 1 which inductively links the blowout magnet 3 with the operating magnet 6.

Thus, during the transient period, when the relay operating coil is energized to close the relay contacts or deenergized to open the relay contacts, a current is induced in the copper loop 1. This sets up a magnetic flux inthe blowout magnet and across the contact gap, to cause the arc, which is developed across the relay contacts l2, is, to blow out.

Some of the advantages of arc blowout by induction are as follows: First, since a blowout coil in the usual sense is not required, there is, consequently, no necessity for replacing such a coil during the life of the interrupter. Also, since heat generation is reduced to a minimum, even replacement of the conducting strap 1 is not necessary. Secondly, as is evident from the drawing, the invention readily lends itself to a simple and economical construction. Thirdly, in utilizing my invention I am not limited to any particular current range which is necessary when employing a series-current type blowout. Also my invention is not dependent on the voltage of theclosing coil circuit inasmuchasthereisno direct electrical connection interconnecting the conducting strap I and the closing coil II. This is a distinct advantage over the shunt blowout scheme in which the voltage on the blowout coil circuit is directly dependent upon the operating voltage. Fourthly, it will be apparent from the foregoing description that the blowout circuit 01' my invention is energized only during the period when it is actually required, that is, during the initiation oi both the opening and closing operations. Thus, there is a minimum 0! heat generated in the blowout coil circuit.

From the foregoing description of certain embodiments of my invention, it will be apparent that some advantages of the disclosed method or setting up a blowout field are that the blowout action is obtained only at the time of interruption, or during closing during sparkover when such blowout action is desired, and that the induction method applied eliminates parts and renders the resulting arrangement exceedingly aimplified.

Although I have shown and described specific structures, it is to be clearly understood that the same were merely for the purpom of illustration and that changes and modifications may readily be made therein by those skilled in the art, without departing from the spirit and scope of the appe ded claims.

I claim as my invention:

1. In a direct-current circuit interrupter, separable contacts to establish an are, operating means for the contacts including an operating magnet having two legs, a blowout magnet having two legs for extinguishing the arc, and conducting strap means coupling one leg or the operating magnet with one leg of the blowout magnet.

2. In a direct-current circuit interrupter, separable contacts to establish an arc, operating means for the contacts including an operating magnet having two legs, a conducting strap encircling one leg, a blowout magnet having two legs to extinguish the arc, and the conducting strap also encircling a leg of the blowout magnet to couple the two magnets together. 3. In a direct-current circuit interrupter, separable contact means Ior establishing an arc, operating means for causing the separation of the separable contact means including an operating magnet, an operating coil for setting up magnetic flux in the operating magnet, a mag netic blowout structure for assisting in the extinction of the arc, and a current conducting loop circuit linking the operating magnet with the magnetic blowout structure to induce magnetic ilux in the latter upon a change of magnetic fiux in the operating magnet.

4. In a direct-current circuit interrupter, a relatively stationary contact, a movable contact separable from the stationary contact to establish an arc, an operating magnet including a movable armature carrying the movable contact, an operating coil for setting up magnetic fiux in the operating magnet to thereby cause closure of the contacts, a magnetic blowout structure for assisting in the extinction of the arc, and a current conducting loop circuit linkin the operating magnet with the magnetic blowout structure to induce magnetic fiux in the latter upon a. change of magnetic fiux in the operating magnet.

5. In a direct-current circuit interrupter, separable contact means for establishing an are, operating means for causing the separation of the separable contact means including an operating magnet, an operating coil for setting up magnetic flux in the operating magnet, a blowout magnet for assisting in the extinction of the arc, and current conducting means coupling the operating magnet with the blowout magnet to induce magnetic flux in the blowout magnet upon a change of magnetic flux in the operating magnet.

6. In a direct-current circuit interrupter, a relatively stationary contact, a movable contact separable from the stationary contact to establish an are, an operating magnet including a movable armature carrying the movable contact, an operating coil for setting up magnetic flux in the operating magnet to thereby cause closure of the contacts, a blowout magnet for assisting in the extinction of the arc, and current conducting means coupling the operating magnet with the blowout magnet to induce magnetic flux in the blowout magnet upon a change of magnetic flux in the operating magnet.

7. A direct-current circuit interrupter including separable contact means for establishing an arc,operating means for causing the separation of the separable contact means including an operating magnet, an operating-coil for setting up magnetic flux in the operating magnet, the operating magnet being energized during each closing operation of the circuit interrupter and being deenergized during each opening operation of the circuit interrupter, a magnetic blowout structure for assisting in the extinction of the arc, and a current conducting loop circuit linking the operating magnet with the magnetic blowout structure so that during the energization and deenergization of the operating magnet magnetic blowout flux may be inductively generated in the magnetic blowout structure.

8; A direct-current circuit interrupter including a relatively stationary contact, a movable contact separable from the stationary contact to establish an arc, an operating magnet including a movable armature carrying the movable contact, an operating coil for setting up ,magnetic flux in the operating magnet to thereby causev closure of the contacts, the operating magnet being energized during each closing operation of the circuit interrupter and being deenergized during each opening operation of the circuit interrupter, a magnetic blowout structure for assisting in the extinction of the arc, and a current conducting loop circuit linking the operating magnet with the magnetic blowout structure so that during the energization and deenergization 01' the operating magnet magnetic blowout flux may be inductively generated in the magnetic blowout structure.

9. A direct-current circuit interrupter including separable contact means for establishing an are, operating means for causing the separation of the separable contact means including an operating magnet, an operating coil for setting up magnetic flux in the operating magnet, the operating magnet being energized during each closing operation of the circuit interrupter and being deenergized during each opening operation of the circuit interrupter, a blowout magnet for assisting in the extinction of the arc, and current conducting means coupling the operating magnet with the blowout magnet so that during the energization and deenergization of the operating magnet magnetic blowout flux may be inductively generated in the blowout magnet.

10. A direct-current circuit interrupter including a relatively stationary contact, a movable contact separable from the stationary contact to establish an are, an operating magnet including a movable armature carrying the movable contact, an operating coil for setting up magnetic flux in the operating magnet to thereby cause closure of the contacts, the operating magnet being energized during each closing operation of the circuit interrupter and being deenergized during each opening operation of the circuit interrupter, a blowout magnet for assisting in the extinction of the arc, and current conducting means coupling the operating magnet with the blowout magnet so that during the energization and deenergization of the operating magnet magnetic blowout flux may be inductively generated in the blowout magnet.

. JOHN C. PONSTINGL.

REFERENCES CITED The following references are 01 record in the file of this patent:

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